Harmon Kardon 930 receiver weak left channel

My HK 930 has worked well for a long time but recently the left channel has gotten very weak. I have to turn the balance control about 3/4 to 7/8 turn to the left to equalize channel volume. I'm not an electronics pro but am willing to take a stab at tracking down the problem if it's not way too involved. Anyone have suggestions?
Thanks!
 
If the problem is internal, I would first suspect switches, particularly the tape monitor. Switch the speakers to make sure you don't have a bad speaker. Check the integrity of the speaker connections too.

The tape monitor switch is always a potential culprit because all the audio goes through it and it seldom gets exercised, opening the door to creeping corrosion.
 
The 930 has a pre-out mainamp- in link at the back you can take out the links and wire the left channel pre to the right power amplifer using a phono to phono lead also cross over the right pre to left power this will show if the problem is in the pre or power amp
then you need to take further steps
I have very many Hk in my collection the fault could be any no of things
regards Trevor
 
Thanks Trevor...what am I looking for when I re-connect the pre and power amps? I found the links, connected an RCA cable to the pre and power amps as you indicated. Using headphones, I found the right channel still noticeably stronger than the left. I'm not really sure what I'm listening for however? Unfortunately, I'm a newbie at this sort of thing and fear my lack of expertise keeps me from self-diagnosing the problem...

Fred
 
you must get a phono to phon lead
pull out the connecting links between the pre-out to power in
then using the phono lead connect the left pre-out to the right poweramp in connect the right preamp out to the left power amp in
if the fault changes sides the fault is in the pre section if it stays the same side its in the power section
the hk of this age have two main problems faulty caps and faulty transistors
do this test first so that we know where the fault is
regards trevor
 
Trevor,
Thanks for walking me through...the fault does change sides so I assume the problem lies in the pre-amp section. Not to abuse your kindness, but can you suggest what I do now to locate the offending component(s)? I can solder fairly well and have done some component replacements on other units so I'm willing to replace bad caps, et al if I know which ones are bad. I just need guidance...Thanks!

Fred
 
Well I am pleased well done but the fault should not have changed sides!
Yep HK fit a resistor across the Ls fuse this then allows the channel to run at a very reduced level but will not allow enough current through to damage your spk should there be a fault.
Great equipment that range
best regards Trev
 
hk 930 channel weak

I know this is an old thread but I’ll try my luck anyways….I have a HK 930 with a weak right side channel and did the pre/main amp swap as you suggested and the output DID change to the other speaker so….I suppose the problem is in the main amp.
Any suggestions as to what to do or try next?
Thanks
 
Yes the transistors need to be very high gain, a lousy design. Many phono preamplifiers suffered from this. I don't recall the current state of this unit but yes I still have it. It was given to me to repair but the owner never contacted me again. It's been several years and it's now just taking up space in my spare room. If you want it, let me know. As I recall, it was awaiting repair still, and perhaps now I have stock of transistors that would work. Nobody seems to use these old turkeys any more.
 
Its more than likely either of the following
Coupling capacitors that have died out
Small signal transistors that have failed I can remember even twenty years ago having to replace the small signal transistors in the tone stage all of them failed in one way or another
Best of luck Trev